3GPP LTE (3rd Generation Partnership Project Long Term Evolution) system has been designed in a frame structure having a transmission time interval (TTI) of 1 ms, and its data request latency time for a video application is 10 ms.
However, the future 5G technology requires data transmission of lower latency due to the advent of a new application such as real-time control and tactile internet, and it is expected that 5G data request latency will be lowered to reach 1 ms. Also, the future 5G technology requires more massive UE connectivity for one base station, and it is expected that 5G requirement connectivity will be increased to maximum 1,000,000/km2.